The present invention relates to a microstrip arrangement, preferably a single-frequency antenna arrangement for use within the microwave range.
Microstrip technology is commonly used in arrangements within higher frequency ranges, for example the microwave range. Microstrip arrangements usually comprise a plane layer of an electrically conductive material arranged on a substrate of dielectric material. A common area of application for microstrip arrangements is antennas.
An extremely important and cost-influencing parameter in previously known microstrip arrangements is the material that is used as the dielectric substrate. The material for the dielectric substrate is extremely important in known microstrip arrangements on account of inter alia the field losses that occur in the dielectric. In order to minimize these field losses, it has been necessary to use dielectric materials that are relatively expensive in previously known microstrip arrangements.
A further problem may be material variations between different deliveries of one and the same dielectric material from one and the same manufacturer.
One known way of reducing the field losses in the dielectric substrate in a microstrip arrangement is to provide the electrically conductive material with a non-plane shape. A disadvantage of this solution is that a non-plane shape drives up the manufacturing cost. Certain losses also occur in the electrically conductive material itself, compared with when the material is of plane shape.
Another type of loss that may arise on account of the properties of the dielectric material is reflection losses, in other words losses at the point where the microstrip arrangement is connected to other equipment, in the case of an antenna especially transmitting or receiving equipment.
American Patent U.S. Pat. No. 4,521,755 discloses an arrangement which aims to improve the electrical properties in a transmission line made using strip line technology. This arrangement is dependent for its functioning on being positioned in a longitudinal cavity formed in a solid metal piece, which would seem to have the effect of making the arrangement bulky as well as costly to manufacture. The arrangement also requires the use of relatively expensive dielectric material, for example RT/DUROID 6010.RTM..